Research Paper

Journal of Nanoparticle Research

, Volume 11, Issue 3, pp 665-670

The third-order optical nonlinearity and upconversion luminescence of CdTe quantum dots under femtosecond laser excitation

  • Qinhan JinAffiliated withResearch Center for Analytical Instrumentation, College of Information Science and Engineering, Zhejiang University Email author 
  • , Wenzhi WuAffiliated withSchool of Electronic Engineering, Heilongjiang University
  • , Zhiren ZhengAffiliated withCenter for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology Email author 
  • , Yuxi YanAffiliated withJilin Province Research Center for Engineering and Technology of Spectral Instruments, Jilin University
  • , Weilong LiuAffiliated withCenter for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology
  • , Aihua LiAffiliated withCenter for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology
  • , Yanqiang YangAffiliated withCenter for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology
  • , Wenhui SuAffiliated withCenter for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology

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Abstract

The aqueous CdTe quantum dots (QDs) were synthesized by the electrostatic reaction method. The optical properties of CdTe QDs were investigated by femtosecond Z-scan and time-resolved luminescence technique in nonresonant spectral region. The nonlinear absorption and refraction are ascribed to two-photon absorption, and time-resolved upconversion photoluminescence produces biexponential decay pattern at infrared femtosecond laser excitation. Upconversion luminescence is composed of a band-edge excitonic state and a photoinduced trapping state. The short-lived band-edge excitonic emission is independent of the detection wavelengths, and long-lived species becomes even longer with the increase of detection wavelengths, which indicates the size dependence of surface excitonic emission.

Keywords

CdTe Quantum dots Optical nonlinearity Time-resolved luminescence dynamics Nanomaterials